This invention pertains to the art of machinery drive mechanisms and more particularly to so-called inching devices for such machinery.
The invention is particularly applicable to a hydraulic inching device for grinding mills utilized in the ore mining and processing environments and will be described with particular reference thereto. However, it will be appreciated by those skilled in the art that the invention has broader applications and may be used in conjunction with other types of machinery for obtaining incremental or inching movement thereof.
So-called inching movement for machinery, in particular, an ore grinding mill for which the subject invention is particularly designed, is desired for installation and periodic maintenance purposes. The inching device simply allows the machinery or mill to be selectively incrementally moved through its normal operative cycle at a much slower rate of speed than is effected by the main or primary drive means. With regard to grinding mills or the like, the capability for inching the mill is particularly desired for purposes of assuring proper gear, shaft and bearing alignment when a mill is first being installed and for work in relining the mill at such time that the liners become worn and are no longer effective.
Manufacturers of various types of ore grinding mills and auxiliary equipment such as gearing may provide some type of inching arrangement with the mills themselves. These inching devices range from the very simple, purely mechanical devices to more exotic or sophisticated electrically powered devices. The simplest mechanical device utilized merely comprises a cable sling arrangement attached to an overhead crane which allows for selective mill rotation. Such operation is not, however, positive or precise and further requires continuous use of a crane so that it is not available for other work activities. It is also dangerous to personnel who may be installing or relining the mill, as slings have a known tendency to break. The more sophisticated electrical devices are costly. Because of the size of a typical ore grinding mill, these inching devices must also, in turn, be of sufficient size to properly drive the mill during an inching operation. This size adds substantial costs to the mill installation. Moreover, and since an inching device is used periodically as noted above, the necessity for having a separate inching device for each mill is not deemed to be cost effective.
The present invention contemplates new and improved apparatus which overcomes all of the above referred to problems and others and provides an inching device particularly suited for heavy machinery such as ore grinding mills and the like which is simple, economical, safe, readily portable from one grinding mill installation to another, does not require any separate or special supporting framework and which is readily dapted to use in a number of machinery environments for inching purposes.